Backlight assembly, and display apparatus and television comprising the same

Abstract

A backlight assembly including: a power unit which outputs a current whose polarity is changed on a regular basis; a plurality of balancing units which is connected in parallel to the power unit; a plurality of light emitting diode (LED) modules each of which individually receives each current output by a corresponding balancing unit of the plurality of balancing units; and a driver which is connected between the plurality of balancing units and the plurality of LED modules, and forms a current route for each balancing unit included in the plurality of balancing units to balance a current supplied to two different LED modules during a single period where a polarity of a current output by the power unit is changed.

What is claimed is: 
     
       1. A display apparatus, comprising:
 a liquid crystal display (LCD) panel which displays an image thereon; and 
 a backlight assembly which emits light to the LCD panel, wherein the backlight assembly comprises:
 a power unit which outputs a current whose polarity is changed on a regular basis; 
 a plurality of balancing units which is connected in parallel to the power unit; 
 a plurality of LED modules which individually receives each current output by one of the plurality of balancing units; and 
 a driver which is connected between the plurality of balancing units and the plurality of LED modules, and forms a current route for each balancing unit to balance a current supplied to two different LED modules during a single period where the polarity of the current output by the power unit is changed, 
 wherein each of the plurality of light emitting diode (LED) modules comprises a plurality of LEDs, and wherein the driver comprises: a first diode line which forms a first current route supplying a current output by a first end of the transformer to a first LED module if the current output by the power unit is positive; and a second diode line which forms a second current route supplying a current output by a second end of the transformer to a second LED module if the current output by the power unit is negative. 
 
 
     
     
       2. The display apparatus according to  claim 1 , wherein the current supplied to the plurality of LED modules is equally balanced during the single period where the polarity of the current output by the power unit is changed. 
     
     
       3. The display apparatus according to  claim 2 , wherein the power unit comprises:
 a power factor compensator which compensates for a power factor of primitive power; 
 an inverter which converts a direct current whose power factor is compensated for, into an alternating current; and 
 a transformer which transforms the alternating current as a primary current into a secondary current. 
 
     
     
       4. The display apparatus according to  claim 3 , wherein the plurality of balancing units comprises a balancing capacitor which is connected to at least a first end of a secondary coil included in the transformer. 
     
     
       5. The display apparatus according to  claim 3 , wherein the inverter is a half bridge type or a full bridge type. 
     
     
       6. The display apparatus according to  claim 3 , wherein the plurality of balancing units is connected in parallel to a single secondary coil included in the transformer. 
     
     
       7. The display apparatus according to  claim 3 , wherein the plurality of balancing units is connected to a plurality of secondary coils included in the transformer. 
     
     
       8. The display apparatus according to  claim 1 , further comprising a driving controller which detects a current flowing in the plurality of LED modules, generates a control signal to control the detected current to become a predetermined reference current, and outputs the control signal to the power unit. 
     
     
       9. The display apparatus according to  claim 8 , wherein the driving controller performs a variable frequency control or a fixed frequency control. 
     
     
       10. The display apparatus according to  claim 1 , further comprising:
 a broadcasting receiver which receives a broadcasting signal; and 
 a signal processor which processes the received broadcasting signal. 
 
     
     
       11. The display apparatus according to  claim 10 , wherein the transformer comprises an insulating transformer. 
     
     
       12. A display apparatus, comprising:
 a liquid crystal display (LCD) panel which displays an image thereon; and 
 a backlight assembly which emits light to the LCD panel, the backlight assembly comprising:
 a power unit which outputs a current whose polarity is changed on a regular basis, 
 a plurality of balancing units which is connected in parallel to the power unit, and each of which receive and balance the current output by the power unit and supplied to two different LED modules, 
 a plurality of LED modules each of which individually receive the respective current output by a corresponding balancing unit of the plurality of balancing units, and 
 a driver which is connected between the plurality of balancing units and the plurality of LED modules, and which forms a current route for each of the plurality of balancing unit to balance the current supplied to the two different LED modules among the plurality of LED modules during a single period where the polarity of the current output by the power unit is changed, 
 wherein each of the plurality of light emitting diode (LED) modules comprises a plurality of LEDs, and wherein the driver comprises: a first diode line which forms a first current route supplying a current output by a first end of the transformer to a first LED module of the plurality of LED modules if the current output by the power unit is positive; and a second diode line which forms a second current route supplying a current output by a second end of the transformer, different from the first end, to a second LED module, of the plurality of LED modules, different from the first LED module, if the current output by the power unit is negative. 
 
 
     
     
       13. The display apparatus according to  claim 12 , wherein the plurality of balancing units equally balance the current during the single period where the polarity of the current output by the power unit is changed. 
     
     
       14. The display apparatus according to  claim 13 , wherein:
 the power unit comprises:
 a power factor compensator which compensates for a power factor of input primitive power, 
 an inverter which converts a direct current whose power factor is compensated for by the power factor compensator, into an alternating current, and 
 a transformer which transforms the alternating current as a primary current into a secondary current, and which comprises a secondary coil; and 
 
 the plurality of balancing units each comprise a balancing capacitor which is connected to at least a first end of the secondary coil. 
 
     
     
       15. A television, comprising:
 a broadcasting receiver which receives a broadcasting signal; 
 a signal processor which processes the received broadcasting signal; 
 a liquid crystal display (LCD) panel which displays the processed broadcasting signal thereon; and 
 a backlight assembly which emits light to the LCD panel, the backlight assembly comprising:
 a power unit which outputs a current whose polarity is changed on a regular basis, 
 a plurality of balancing units which is connected in parallel to the power unit, and each of which receive and balance the current output by the power unit and supplied to two different LED modules, 
 a plurality of light emitting diode (LED) modules each of which individually receive the respective current output by a corresponding balancing unit of the plurality of balancing units, and 
 a driver which is connected between the plurality of balancing units and the plurality of LED modules, and which forms a current route for each of the plurality of balancing units to balance the current supplied to the two different LED modules among the plurality of LED modules during a single period where the polarity of the current output by the power unit is changed, 
 wherein each of the plurality of light emitting diode (LED) modules comprises a plurality of LEDs, and wherein the driver comprises: a first diode line which forms a first current route supplying a current output by a first end of the transformer to a first LED module of the plurality of LED modules if the current output by the power unit is positive; and a second diode line which forms a second current route supplying a current output by a second end of the insulating transformer, different from the first end, to a second LED module of the plurality of LED modules, different from the first LED module, if the current output by the power unit is negative. 
 
 
     
     
       16. The television according to  claim 15 , wherein the plurality of balancing units equally balance the current during the single period where the polarity of the current output by the power unit is changed. 
     
     
       17. The television according to  claim 16 , wherein the power unit comprises:
 a power factor compensator which compensates for a power factor of input primitive power; 
 an inverter which converts a direct current, whose power factor is compensated for by the power factor compensator, into an alternating current; and 
 an insulating transformer which transforms the alternating current as a primary current into a secondary current. 
 
     
     
       18. The television according to  claim 17 , wherein:
 the insulating transformer comprises a secondary coil; and 
 the plurality of balancing units each comprise a balancing capacitor which is connected to at least a first end of the secondary coil. 
 
     
     
       19. A method of balancing a current supplied to a plurality of light emitting diode (LED) modules of a backlight assembly, the method comprising:
 receiving, by a plurality of balancing units connected in parallel to a power source, a current whose polarity is changed on a regular basis from the power source; 
 supplying, by each of the plurality of balancing units, the current to two different LED modules, respectively, among the plurality of LED modules during a single period where the polarity of the current is changed, 
 wherein each of the balancing units supplies the current to one of the two different LED modules when the polarity of the current is positive and an other of the two different LED modules when the polarity of the current is negative, 
 wherein each of the plurality of light emitting diode (LED) modules comprises a plurality of LEDs.